Growth of entropy corresponds to an increase in the number of molecular complexions.
(6) Finally we give a mathematical concept which covers the whole domain of physics: "Any function whose time variation always has the same sign until a certain state is reached and is then zero, may be called an entropy function."
[18]This need cause no surprise, for it is only very recently that the conviction is gaining ground that the Second Law has no independent significance, but that its full content will only be grasped when its roots are sought in the Theorems of the Calculus of Probabilities.
[SECTION F]
MORE PRECISE AND SPECIFIC STATEMENTS OF THE SECOND LAW
We have here classified these statements in the same way as that followed in the preceding section, when grouping the general equivalents of the Second Law under the head of change of entropy. In making comparisons we must, here as there, bear in mind the following three helpful propositions:
(a) The summary of all the necessary prerequisites (or conditions) for determining entropy may be regarded as a complete and valid statement of the second law.
(b) Any general consequence of any one correct statement of the second law may be regarded as itself a valid and complete statement of the second law.
(c) All cases of irreversibility stand or fall together; if any one of them can be completely reversed all can be so reversed.
In the preceding section we have already given the most precise physical statement of the Second Law, namely, when all the participating bodies of the system are considered, every natural event is marked by an increase in the number of complexions of the system. We have numbered the following statements of the second law, for convenience of reference: